Microwave oven



FIG. 1 is a front, right perspective of the microwave oven showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof, with the right side view being a mirror image thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof.

The broken line showing of environment in the drawings is included for the purpose of illustrating only and forms no part of the claimed design. 

The ornamental design for a microwave oven, as shown and described. 